Multilayer storage container

ABSTRACT

A multiple layer reusable plastic container is disclosed. The multiple layer structure includes at least one layer of recycled or highly economic material and at least one outer layer made from either virgin resin or a more aesthetically appealing material to provide a multiple layer reusable container that is economical to manufacture in terms of material costs but yet has an acceptable outward appearance. The recycled or economical layer may be coated on both sides with virgin resin to provide an improved inner and outer appearance to the reusable container and also qualify the inner surface as an appropriate food contacting surface.

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit under 35 U.S.C. § 119(e) ofU.S. Provisional Patent Application Serial No. 60/301,540, filed Jun.27, 2001, the disclosure of which is incorporated herein by reference.

BACKGROUND

[0002] 1. Technical Field

[0003] Reusable plastic storage containers are disclosed. Morespecifically, reusable plastic storage containers having a multiplelayer structure are disclosed. Still more specifically, reusable plasticstorage containers are disclosed that have a multiple layer structurewherein at least one of the layers is fabricated from recycled plasticor other economical polymer material and wherein at least one of thevisible outer layers is fabricated from virgin resin material.

[0004] 2. Description of the Related Art

[0005] Reusable storage containers are known. One common type ofreusable storage containers is fabricated from molded plastic in theform of an open-top box with a molded plastic lid. Such containers comein a variety of styles and colors.

[0006] One problem associated with currently available reusable storagecontainers is the relatively high manufacturing cost. Specifically,because the containers need to be aesthetically appealing due to theirextended use, virgin resins are typically used in their fabrication.Colorants are added to impart any of a variety of colors to thecontainers. Because of the aesthetic appeal requirement, post-consumerregrind or post-industrial regrind resins are generally unacceptablebecause these recycled resins may include large quantities ofcontaminants, which give the resulting product a speckled andinconsistent appearance. As a result, the manufacturer may have to finda source or recycled material or regrind resin of a higher quality or ofa desired color, which may drive up the cost of using a regrind resin.

[0007] Further, because reusable containers must be relatively rigid topermit stacking and carrying of heavy items, large quantities of virginresins are used to fabricate a single container and lid combination.Because the containers are typically injection- or blow-molded, most ofthe cost of manufacture is tied up in materials costs. As a result, therequirement that virgin resins be used substantially drives up the costof currently available reusable containers.

[0008] As a result, there is a need for improved reusable plasticcontainer designs and methods of manufacture which can decrease the costof manufacture of these items.

SUMMARY OF THE DISCLOSURE

[0009] A more economical reusable three-dimensional storage container isdisclosed.

[0010] In one refinement of the disclosure, a reusable three-dimensionalstorage container includes a first layer of a post-consumer orpost-industrial regrind resin selected from the group consisting oflinear low density polyethylene, high density polyethylene,polyvinylchloride and polyethyleneterephtalate, and a second layer of avirgin resin that is tied to the first layer. Preferably, the secondlayer serves as an outer layer to provide the requisite aestheticappearance. However, it is anticipated that the second layer might serveas an inner layer in the event the reusable storage container isintended to hold food products and therefore the second layer isintended to be a food-contacting surface.

[0011] In a refinement, the container further includes a third layerdisposed adjacent the first layer, opposite from the second layer. Thethird layer includes a virgin resin material, thereby providing areusable three-dimensional storage container having three layers, twovirgin resin layers which sandwich a recycled, regrind or othereconomical polymer layer therebetween.

[0012] In a further refinement of the disclosed container, the virginresin layer(s) may include a colorant.

[0013] In still a further refinement of the disclosed container, a ratioof the thicknesses of the first layer to the thickness of either thesingle second layer or the combined thicknesses of the second and thirdlayers ranges from about 60:40 to about 80:20. As a result, the bulk ofthe material used to fabricate the reusable storage container is eithera recycled resin or an economical resin thereby substantially loweringthe overall cost of the reusable container.

[0014] The economical or recycled first layer may also include a foamingagent to reduce the weight of the container or a filler such as calciumcarbonate which will reduce the molded part cooling time.

[0015] Other advantages of the disclosed container will be apparent tothose skilled in the art from a review of the following figures anddetailed description taken in conjunction with the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The disclosed containers are described diagrammatically in thefollowing drawings wherein:

[0017]FIG. 1 is a sectional view of a multilayer material used tofabricate a reusable storage container made in accordance with thedisclosure;

[0018]FIG. 2 is a sectional view of another multilayer material used tofabricate a reusable storage container made in accordance with thedisclosure;

[0019]FIG. 3 is a front sectional view of a reusable storage containerand lid combination made in accordance with the disclosure;

[0020]FIG. 4 is an end sectional view of the container shown in FIG. 3;

[0021]FIG. 5 is an enlarged partial end view of the container shown inFIG. 3;

[0022]FIG. 6 is a top plan view of the container shown in FIG. 3 withthe lid removed;

[0023]FIG. 7 is a perspective view of the container shown in FIG. 3 withthe lid removed;

[0024]FIG. 8 is a front sectional view of two reusable storagecontainers as shown in FIG. 3 stacked one on top of another;

[0025]FIG. 9 is a sectional view of two parisons used to fabricate a twolayer reusable storage container in accordance with the disclosure; and

[0026]FIG. 10 is sectional view of three parisons used to fabricate areusable container in accordance with the disclosure.

[0027] The drawings are not necessarily to scale and that theembodiments are sometimes illustrated by graphic symbols, phantom lines,diagrammatic representations and fragmentary views. In certaininstances, details which are not necessary for an understanding of thedisclosed containers or which may render other details difficult toperceive may have been omitted. It should be understood, of course, thatthe disclosure is not necessarily limited to the particular embodimentsillustrated herein.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

[0028]FIG. 1 illustrates a two layer structure including a first layer20 tied to a second layer 21. In order to reduce manufacturing costs, ofwhich approximately 50% are due directly to the cost of materials andcolorant, the first, thicker layer 20 can be fabricated from apost-consumer regrind or post-industrial regrind resin such as linearlow density polyethylene, high density polyethylene, polyvinylchloride,polyethyleneterephthalate, nylon and mixtures thereof. Other,inexpensive resins may also be used to drive down the manufacturingcosts, which will be apparent to those skilled in the art. The thinner,second layer 21 is preferably fabricated from a virgin resin to providean improved outer appearance to a container or to provide a satisfactoryfood-contacting surface. Suitable resins for the second layer 21include, but are not limited to, linear low density polyethylene, highdensity polyethylene, polyvinylchloride, polyethyleneterephthalate,nylon and mixtures thereof. Other suitable resins will be apparent tothose skilled in the art depending upon the qualities desired (e.g.,scratch resistance, stain resistance, resistance to oxidation, etc.).

[0029] Often, it is desirable to have either an improved inner and outerappearance to a reusable container or to provide an aestheticallyappealing outer surface wall providing a suitable food-contacting innersurface. In such cases, containers can be fabricated from the threelayer structure shown in FIG. 2 which includes a first layer 20, asecond layer 21 and a third layer 22. The layer 22 can be made from likeor similar materials as used for the layer 21 discussed above.

[0030] Suitable colorants for the outer and inner layers 21, 22 include,but are not limited to, various organic and inorganic pigments dispersedin a polyolefin carrier. Further, to reduce the weight of the overallstructure formed, foaming agents can be used in the layer 20. Suitablefoaming agents include, but are not limited to, citric acid mixed withsodium bicarbonate.

[0031] In addition, fillers may be added to the thicker layer 20 toreduce the cooling time of the molded part, reduce the gloss or sheen ofthe product and/or stiffen the resulting product. One suitable filler iscalcium carbonate. Other suitable fillers include, but are not limitedto, talc, barium sulfate, mica, glass, clay, titanium dioxide, dolomite,wood flower and flax.

[0032] Other functional properties may be incorporated into the innerand outer layers 22, 21, such as stain resistance. If stain resistanceis desired for either layer 22, 21, the layers should incorporate astain-resistant resin including, but not limited to, polysulphone,polymethylpentene, polycarbonate, polyetherimide, nylon, polyarylate,polyphenylsulphide, polyphenylene oxide, polyethersulphone,polyethyleneterephtalate, aromatic polyketone, liquid crystal polymerand mixtures thereof.

[0033] Further, fragrance can be added to any of the layers 20-22.Suitable fragrance includes various fragrance oils dispersed in apolyolefin carrier. Further, odor fighting additives, such as sodiumbicarbonate can be added to one or more of the the resins utilized.Still further, using a foaming agent in at least the middle layer 20,and perhaps the outer layers 21, 22, can increase the insulatingproperties of the resulting container.

[0034]FIG. 3 is a partial elevational/sectional view of a container 25that can be fabricated from either the two-layer structure of FIG. 1 orthe three layer structure of FIG. 2 as discussed above. Container 25includes a lid 26 secured to an open-top container 27. Container 27includes bottom panel 28 disposed between and connected to opposing endpanels 29, 31 as well as side panels 32, 33 (see also FIG. 7). Thecontainer portion 27 typically includes handles 30, 34. Further, toenhance sealing, the handles 30, 34 may include a bead 35, 36 aroundwhich a lip 37, 38 of the lid 26 is secured to provide a secureengagement. The side panels 32, 33 may also include recessed sections41-44 (see also FIG. 7). The recess sections 41-44 enhance thestructural integrity of the container 27. Further, as discussed belowwith respect to FIGS. 9-10, the recess sections 41-44 may also serve asa transparent window to make it easy for the consumer to view thecontents of the container 27. Similarly, as shown in FIGS. 4 and 7, theend panels 29, 31 may also include recesses 45, 46. As shown in FIG. 8,the recesses 41-46 also enhance the stackability of two light containerportions 27 a, 27 b.

[0035] Turning to FIGS. 9 and 10, a preferred method for fabricating thereusable containers disclosed above is a co-extrusion blow moldingprocess. In such a process, a parison 50 as shown in FIG. 9 isco-extruded so that it has an inner layer 20 and an outer layer 21 (seeFIG. 1). The parison 50 may then be blow molded into a three dimensionalarticle such as the container portion 27 or lid portion 26 of thecontainer assembly 25 shown in FIG. 3. In the embodiment shown in FIG.9, clear resins are provided at 51, 52 to provide a window at one of therecesses 41-46 of either the side panels 32, 33 or end panels 29, 31 asshown in FIGS. 3, 4, and 7-8. Similarly, as shown in FIG. 10, a parison60 may be provided with co-extruded layers 20-22 (see FIG. 2). Again,clear portion 61, 62 may be provided for purposes of a viewing “window”as described above.

[0036] The thickness of the layers 20-22 can vary, depending upon theembodiment. Preferably, the thickness of the layer 20 is at least twiceas thick as the layer 21 in a two layer structure or the layer 20 is atleast twice as thick as the combined thicknesses of the layers 21, 22 ina three layer structure. Suitable thickness ratios of the thickness ofthe layer 20 to the thickness of the layer 21 (two layer structure) orto the combined thicknesses of the layers 21, 22 (three layer structure)can range from about 50:50 to about 80:20.

[0037] The foregoing detailed description is given for clearness ofunderstanding only, and no unnecessary limitation should be understoodtherefrom, as modifications within the scope of the invention may becomeapparent to those skilled in the art.

What is claimed:
 1. A reusable, three-dimensional storage containercomprising: a first layer comprising a post-consumer or post-industrialregrind resin selected from the group consisting linear low densitypolyethylene, high density polyethylene, polyvinylchloride,polyethyleneterephthalate, nylon and mixtures thereof, a second layercomprising virgin resin tied to the first layer.
 2. The storagecontainer of claim 1 wherein the first layer serves as an inner layerand the second layer serves as an outer layer.
 3. The storage containerof claim 1 wherein the second layer further comprises a colorant.
 4. Thestorage container of claim 1 further comprising a third layer comprisingvirgin resin material disposed adjacent the first layer opposite fromthe second layer, the third layer being tied to the first layer.
 5. Thestorage container of claim 4 wherein the second layer further comprisesa colorant.
 6. The storage container of claim 4 wherein the third layerfurther comprises a colorant.
 7. The storage container of claim 4wherein the second and third layers each comprise a colorant.
 8. Thestorage container of claim 1 wherein a ratio of thicknesses of the firstto the second layer ranges from about 60:40 to about 80:20.
 9. Thestorage container of claim 4 wherein a ratio of a thickness of the firstlayer to a combined thickness of the second and third layers ranges fromabout 50:50 to about 80:20.
 10. The storage container of claim 1 whereinthe first layer further comprises a foaming agent.
 11. The storagecontainer of claim 1 wherein the first layer further comprises calciumcarbonate.
 12. The storage container of claim 4 wherein the first layerfurther comprises a foaming agent.
 13. The storage container of claim 4wherein the first layer further comprises calcium carbonate.
 14. Thestorage container of claim 1 wherein the container is formed using aco-extrusion blow molding process.
 15. A reusable, three-dimensionalstorage container comprising: (a) a container portion comprising a firstlayer comprising a post-consumer or post-industrial regrind resinselected from the group consisting linear low density polyethylene, highdensity polyethylene, polyvinylchloride, polyethyleneterephthalate,nylon and mixtures thereof, a second layer comprising virgin resin tiedto the first layer, a third layer comprising virgin resin materialdisposed adjacent the first layer opposite from the second layer andtied to the first layer, the first, second and third layers of thecontainer portion being molded to form a bottom panel connected to anddisposed between two opposing side panel and two opposing end panels,each side panel being disposed between and connected to the opposing endpanels to form an open top box structure, and, (b) a top portioncomprising a first layer comprising a post-consumer or post-industrialregrind resin selected from the group consisting linear low densitypolyethylene, high density polyethylene, polyvinylchloride,polyethyleneterephthalate, nylon and mixtures thereof, a second layercomprising virgin resin tied to the first layer, a third layercomprising virgin resin material disposed adjacent the first layeropposite from the second layer and tied to the first layer, the first,second and third layers of the top portion being molded to form a toppanel that engages top edges of the side and end panels of the containerportion to provide a lid for the open box structure.
 16. The storagecontainer of claim 15 wherein the second and third layers furthercomprise a colorant.
 17. The storage container of claim 15 wherein aratio of a thickness of the first layer to a combined thickness of thesecond and third layers of the container portion ranges from about 50:50to about 80:20 and a ratio of a thickness of the first layer to acombined thickness of the second and third layers of the top portionranges from about 50:50 to about 80:20.
 18. The storage container ofclaim 15 wherein the first layer further comprises a foaming agent. 19.The storage container of claim 15 wherein the first layer furthercomprises calcium carbonate.
 20. The storage container of claim 15wherein the second and third layers comprise a resin selected from thegroup consisting of polysulphone, polymethylpentene, polycarbonate,polyetherimide, nylon, polyarylate, polyphenylsulphide, polyphenyleneoxide, polyethersulphone, polyethyleneterephtalate, aromatic polyketone,liquid crystal polymer and mixtures thereof.
 21. The storage containerof claim 15 wherein the container portion is formed using a co-extrusionblow molding process.
 22. The storage container of claim 15 wherein thetop portion is formed using a co-extrusion blow molding process.
 23. Alid for reusable, three-dimensional storage container, the lidcomprising: a first layer comprising a post-consumer or post-industrialregrind resin selected from the group consisting linear low densitypolyethylene, high density polyethylene, polyvinylchloride,polyethyleneterephthalate, nylon and mixtures thereof, a second layercomprising virgin resin tied to the first layer.
 24. The lid of claim 23further comprising a third layer comprising virgin resin materialdisposed adjacent the first layer opposite from the second layer, thethird layer being tied to the first layer.
 25. The lid of claim 24wherein the second and third layers each comprise a colorant.
 26. Thelid of claim 23 wherein a ratio of thicknesses of the first to thesecond layer ranges from about 60:40 to about 80:20.
 27. The lid ofclaim 24 wherein a ratio of a thickness of the first layer to a combinedthickness of the second and third layers ranges from about 60:40 toabout 80:20.